title: Cyclin-dependent kinase 1-dependent phosphorylation of cAMP response element-binding protein decreases chromatin occupancy.
abstract: The cyclic AMP response element-binding protein (CREB) initiates transcriptional responses to a wide variety of stimuli. CREB activation involves its phosphorylation on Ser-133, which promotes interaction between the CREB kinase-inducible domain (KID) and the KID-interacting domain of the transcriptional coactivator, CREB-binding protein (CBP). The KID also contains a highly conserved phosphorylation cluster, termed the ATM/CK cluster, which is processively phosphorylated in response to DNA damage by the coordinated actions of ataxia-telangiectasia-mutated (ATM) and casein kinases (CKs) 1 and 2. The ATM/CK cluster phosphorylation attenuates CBP binding and CREB transcriptional activity. Paradoxically, it was recently reported that DNA damage activates CREB through homeodomain-interacting protein kinase 2-dependent phosphorylation of Ser-271 near the CREB bZIP DNA binding domain. In this study we sought to further clarify DNA damage-dependent CREB phosphorylation as well as to explore the possibility that the ATM/CK cluster and Ser-271 synergistically or antagonistically modulate CREB activity. We show that, rather than being induced by DNA damage, Ser-270 and Ser-271 of CREB cophosphorylated in a CDK1-dependent manner during G2/M phase. Functionally, we show that phosphorylation of CREB on Ser-270/Ser-271 during mitosis correlated with reduced CREB chromatin occupancy. Furthermore, CDK1-dependent phosphorylation of CREB in vitro inhibited its DNA binding activity. The combined results suggest that CDK1-dependent phosphorylation of CREB on Ser-270/Ser-271 facilitates its dissociation from chromatin during mitosis by reducing its intrinsic DNA binding potential.
authors.affiliation: Department of Human Oncology, Program in Molecular and Cellular Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, USA.
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Trinh
authors.forename: Sang Hwa
authors.initials: SH
authors.lastname: Kim
authors.forename: Hae-yoon
authors.initials: HY
authors.lastname: Chang
authors.forename: Adam S
authors.initials: AS
authors.lastname: Mastrocola
authors.forename: Randal S
authors.initials: RS
authors.lastname: Tibbetts
mesh_terms: D000595:Amino Acid Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D024202:Electrophoretic Mobility Shift Assay; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism
chemical_list: D002843:Chromatin; D017362:Cyclic AMP Response Element-Binding Protein; D010768:Phosphoserine; D004247:DNA; D016203:CDC2 Protein Kinase; D015739:Nocodazole
keywords: CDK (Cyclin-dependent Kinase); CREB; Chromatin; Homeodomain-interacting Protein Kinase 2; Mitosis; Phosphorylation; Transcription Factors